The present invention relates to a communication system, a communication apparatus, an image reception system, and a communication method.
In a communication system where a parent unit and a child unit can carry out data communication with each other via a communication means, such as a wireless LAN (Local Area Network), both the parent unit and the child unit usually have a power switch. To carry out data communication in such a system, power must be turned on to both the parent unit and the child unit. Therefore, when starting the communication system, the power switch on both the parent unit and the child unit must be turned on first. This connects the parent unit and the child unit for establishing wireless LAN communication. In other words, the parent unit and the child unit recognize each other to establish wireless LAN communication. Once communication is established, the parent unit and the child unit can exchange data.
However, in a communication system where wireless communication is carried out between a parent unit and a child unit, the parent unit and the child unit are installed separately in many cases. A burdensome problem with such a system is that both the parent unit and the child unit must be turned on before starting data communication between them.
For example, in a communication system such as the one disclosed in Japanese Laid-Open Patent Application JP2001-203908, where video and audio wireless data communication is carried out between a television set (corresponding to a parent unit) having a large screen display and an auxiliary input/output unit (corresponding to a child unit) having a small-screen touch panel display, both the parent unit and the child unit, usually installed separately, must be turned on before starting wireless data communication. This may constitute a burdensome operation.
In particular, in such a communication system, the child unit receives a broadcast video, received by the tuner included in the parent unit, via wireless communication for displaying it on the display on the child unit side. Thus, even when the user wants to view the broadcast video only on the child unit side, there is a problem that, if the parent unit is not turned on, the user cannot watch the video on the child unit side.
A similar situation occurs when the user wants to view a video on the child unit side, for example, in a communication system where a video, received by a base station (corresponding to a parent unit) having a television tuner but not a display, is received by a display unit (corresponding to a child unit) via wireless two-way communication for displaying the video image thereon.
A problem similar to the one described above may occur in a communication system where wireless two-way communication is carried out between an “Airstation” (trademark of Buffalo Inc.) (corresponding to a parent unit) and a personal computer (corresponding to a child unit). If an “Airstation” device used as a parent unit does not consume considerable power, it may be kept on constantly. In such a case, simply turning on the power of the child unit may start the wireless communication. However, a parent unit such as a display unit on which the broadcast video described above is displayed consumes too much power to be on constantly. This means that it would be convenient for the parent unit to be automatically turned on when the child unit is turned on.
In view of the foregoing, there is a need for a communication system, a communication apparatus, an image reception system, and a communication method for automatically turning the power of a parent unit on by simply turning the power of a child unit on during wireless two-way communication in order to facilitate the operation of the wireless two-way communication